Method of manufacturing piston-rings.



J. F. DODGE (p w. 1'. ALLES. METHOD OF MANUFACTURING PISTON RINGS.

APPLICATION FILED MAYFZ. 19H- Patented Feb. 5, 191 8.

ATTOR/VE YB 1. F. 00mm; & wll. ALLES. METHOD OF MANUFACTURING PISTONRINGS- APPLICATION FILED MAY I2. I91?- Patented Feb. 5,1918.

3 SHEETS-SHEET 2- INVENTOR i4mIA\ s ATTORNEYS Patented Feb. 5, 1918 3SHEETS-SHEET 3.

J. F. DODGE 61 WLJIALLES.

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. INVENTORS JAM FD! w J.- Afles Maw-M ATTORNEYS METHOD OF MAN UFACTURING PISTON RINGS.

UNITED STATES PATENT OFFICE.

JOHN I.

DODGE AN D WILLIAM J. ALLES, OF DETROIT, MICHIGAN, ASSIGNOBS TD DODGEBROTHERS, 015 DETROIT, MICHIGAN, A GORPOBA'I'ION OF MICHIGAN.

METHOD OF MANUFACTURING PISTON-RINGS.

Specification of Letters Patent.

Patented Feb. 5, 1918.

Application filed May 12, 1917. Serial No. 165,111.

This invention relates to an improvedmethod of manufacturing pistonrings for internal combustion engines or those of other types.

One of the objects of this invention is to provide a method by which thestiffness of a piston ring may be. increased and made to varycontinuously around the circumference of the ring that when the ring iscontracted in a cylindcn a practically uni form outward pressure will beexerted at all points of contact between the ring and cyl :inder.

Another object of this invention is the provision of a method for easilyand cheaply increasing the density and stiffness of the material in apiston ring.

The met od of manufacture hereinafter to be described, consists broadlyin com-- pressing'the entire inner surface of the ring in continuouslyvarying degrees around the circumference so that the stiffness of thering against bending in a plane normal to its axis varies continuouslyfrom point to point. This stifi'ei'iing effect is a maximum at the pointdiametrically opposite the gap and gradually decreases around thecircumference from this point to the gap, where it becomes zero.

One method of producing the above described effect is as follows: acylindrical casting, having its internal and external diametersrespectively less than and lar er than the corresponding diameters ofthe nished ring, is bored out to a diameter slightly greater than theinternalf diameter of the finishedu'ing and the exterior of the castingis turned to a diameter slightly larger than the bore of the cylinderwhich it i's to fit. The internal surface of the castingis thencompressed by rolling it with a hardened roller or rollers so that themetal made very hard and dense at the surface, this effect extending toan appreciable distance into the interior of the metal. The casting isthen bored out eccentrically, so

' that the part of the metal which has been affected by the rollingi'sentirelyremoved at one point in thecircumference, while the surface atthe point diametrically opposite is not touched. This has the elfect'ofvarying 'the stiffness of the casting at various points around thecircumference. The casting is then divided on planes perpendicular toits. axis, thus forming solid rings which I are then ground on theirflat faces to produce true surfaces at the proper distance apart. Therings are then sawed throu h at'the point where the material affected ythe rolling has been entirely removed and the proper amount of materialtaken off the ends so that when the ends are brought together, the ringswill have the desired diameter. The rings are then placed in a chuckwhich holds the .ends together while theouter cylindrical surface isground to the exact diameter required. v

A second and alternative method which produces the same effect in aslightly different way is carried out as follows: The cylindricalcasting is first machined to the proper dimensions as described above,but, instead of being rolled uniformly all over its interior surface, itis acted upon by a roller or series of rollers revolving about an axiseccentric to the axis of the casting so that the pressure exerted uponthe casting by the rollers varies at different points in thecircumference. With this process, the eccentric boring operation isunnecessary, but the other operations to complete the ring remain asabove described, these operations consisting in dividing the casting onplanes perpendicular to its axis, thus forming solid ringsin the mannerhereinabove described in connection with the first method, which arethen ground on their flat faces to produce true surfaces at the properdistance'apart; then sawing through each of these rings at the pointwhere the application of the pressure has been least or, in other words,at the point where the tension produced upon the mner surface of thering is least. V This point will obviously coincide with the point ofleast reduction in thickness by the rolling operation.

Qwing to the fact that the omission of the eccentric boring operationmakes this second method somewhat cheaper than the one first described,it is of greater commercial impoltance and this application will bexdee"voted iargeiy'to a and methods useL tice,fl1eugh the, s changes in theI in carryir wt :9 A I Insteasio ing which is pistcn rings I scribekimay, 0 l0 'diviiua rings Referring"- 1;?) Figure; 1 rangemeni; 'su'surface of a Fig. 2 Ma vartisal 5c of Fig.1.-

Fig. is a 40 u 'Which the pismn ring casting K i' 4 is an and; vieW -pimports F lg. 3 shown 53: d 1 7 54:, mhm 5 gf fine used 1.1 twining;Lsuppgriigfi ne r0 4*. 4

Fig. 0 Fig. 5 V Fig: '3' is a jratus shew/L Fig. 8 019; Fig. 9 an aim"arrangement for roliin' 39 piston ring casting I Fig. 10 is a,verfiicvfi sectien :11. A 5 r 1 10--10.0f Fi 12% Fig. a. plan Viewshown.

Fig. 13 arrangemen pissc'n ring Fig: 14-

ii; 1 shown in @1 Fig, 16 is Q M Fig 17 is'au v l L521 rangement for m1ton ring 021 Fig. 18 is a hiili 18-46 of *1}; Fig. 19 s shown i2: F1

Fig. 20 lg. l claanpui in an the. $00 ea fielder is prev;

portion 1?, Whifih is and helcl (5 ing by the sub to fit 51., ring castiof the 6:15. '35 the 1:

roller as described above in connection with the arrangements alreadyillustrated.

Apparatus for performing the rolling operatlon upon a drill press isshown in Fig. 17 Where the bar 30 is driven by the spindle 81 andhas itslower end guided in the bushing 32 carried in the table. The work holder33 is adjustable upon the table to give the desired eccentricity and theposition of the roller relative tothe axis of the bar is also adjustableas described above.

It will be understood hatthe method of this invention may be carried outby other means than those herein described, and in this connection itwillbe noted that there is a relative travel of the means exertingpressure upon the interior of the piston ring casting both about theaxis of the casting and lengthwise of the casting; that in itslengthwise travel this means moves along lines vof equal pressure, andthat as it travels about the axis of the casting the pressure is variedby eccentric increments or decrements having a common axis ofeccentricity. In other words, the pressure at different points about theaxis offthe rin varies by amounts corresponding to the dili erences, atdifferent points in the path of travel of the pressure exerting meansabout said axis, ofthe distances between the inner surfaces of two ringsof unequal diameters which are eccentric toeach other and one of whichcompletely surrounds the other. As the method is practised, the pressureexerted upon the inner surface of the ring along any line parallel tothe axis of the ring will be the same atall points along this line.

What we claim as new is:

1. The method of making piston rings which comprises subjecting theinternal cylindrical surface of the ring to rolling pressure, varyingsaid pressure between a maximum upon one side of the axis of the ringand a minimum upon the opposite side, and progressively advancing theapplication of said pressure along the axis of said ring.

2. The method of making piston rings which comprises subjecting theinternal cylindrical surface of the ring to, rolling pres sure travelinghelically about the axis of said ring and varying said pressure betweena maximum upon one side of said axis and a minimum .upon the oppositeside.

3. The method of makin piston rings which comprises closely con ning theouter cylindrical surface of the ring and then subjecting the innercylindrical surface to rolllng wall compressing pressure, varying saidpressure, as it travels about; the axis of said ring, byeccentric-increments or decrements having a common axis of eccentricity,and advancing the application of said pressure along said axis" in linesof equal pressure.

4. The 'method of making piston rings which comprises closely confiningthe outer cylindrical surface of the ring and then subjectlng the innercylindrical surface to rolling wall compressing pressure, varying saidpressure, as it travels about the axle of said ring, by eccentricincrements or decrements having a common axis of eccentricity, ad;vancmg the application of said pressure along said axis in lines ofequal pressure, and then cutting through said ring at the point wherethe pressure application has been substantially least.

'5. The method of making piston rings which comprises subjecting theinner cylindrical surface of a hollow cylindrical castin ofsubstantially uniform wall section to 1'0 ling wall compressingpressure, varying said pressure, as it travels about the axis of saidcylinder,- by eccentric increments or decreinents having a common axisof eccentricity, advancing the application of said pressureprogressively along said axis in lines of equal pressure, cutting saidcylinder j into rings and then cutting through each ring at the pointwhere the pressure application has been substantially least '6. Themethod of making piston rings which comprises subjecting a hollow'cylinr drical casting of substantially uniform wall section to rollingwall compressing pressure.

varying from point to point around the circunrference, and then cuttingthrough said casting where the resultant internal tension is least.

7 The method of making piston rings which comprises pressing the innerwall of a hollow cylindrical casting of substantially uniform wallsection into the contour "ofa cylinder having its axis parallel buteccentrio 'to that of the outer wall while positivelynnaintaining theexternal shape and then cutting through said wall at its thickest part.

9. The process of making piston rings which comprises continuouslysupporting one side of the wall of a hollow cylindrical casting ofsubstantially uniformjwall sec-' tion and then progressively exertingheavy pressure of varying intensity upon the other side of said Wall.

10. The process of making. piston rings .which comprises subjecting thewall of a hollow cylindrical casting of substantially uniform wallsection to heavy pressureexerted progressively about the axis of thecylinder and varyin gradually from a maX- imum upon one si e ofthecylinder 'to a cylindrical surfaces with axes 5 11L The process ofmaking piston rings,

which comprises subjecting the wall of a hollow cylindrical casting, ofsubstantially uniform Wall section, to heavy pressure exertedprogressively both about and along the 10 axis of the cylinder, andgradually varying said pressure from a maximum at points in a lineparallel to said axis to a minimum at points in a line diametricallyopposite to said first mentioned line, and then back to v 15 saidmaximum.

-12. The improvement in the art of makingpiston rings, which consists inpositively confining a hollow cylindrical casting of substantiallyuniform wall thickness,

2 and then effecting a redistribution of the metal in said casting bypressure exerted progressively and variably along lines preetermined insuch manner. as to tend to form a structure having outer and innereccentric to'each other.

'13. Theimproveinent in the art of making piston rings, which consistsin eifecting a redistribution of the metal in a,.hollow cy- 30 lindricalcasting, oi substantially uniform wall section, by exerting. rollingwall comparallel butpressing pressure progressively variably about theaxis of said cylinder and along lines predetermined to produce astructure having its most compressed portion upon one side anclits leastcompressed portion diametrically opposite to the thinnest position,

' form Wall section and thencompressing said wall .hy rolling pressureapplied upon the 4i inner surface of said casting before forming "theusual pistonring split.

15, The .process of making piston rings, which comprises subjecting thewall ofa hollow cylindrical casting, of substantially 5 uniform Wallsection, to heavy wall compacting pressure exerted progressively bothabout and along the axis of the cylinder before forming the usual pistonring split.

Signed at Detroit, Michigan, this 3rd day 5 of May, 1917.

JOHN FIDODGE. I WILLIAM J. ALLES.

Witnesses REGINALD JOHN FRY, ALFRED H. KNIGHT.

It s hareby certified that in Letters Patent N 0. |,255,142, grantedFebruary 5,

1918, upon the -pp ication of John F. Dodge and William J. Alles, ofDetroit,

Michigan, for an improvement in "Methodsof M artufacturing Piston-Rings,an

error appears in the printed specification requiring correction asfollows: Page 4,

line 37, claim 13, for the'word "positi0n read portion; and that thesaid Letters Patent should be read with this correction therein that thesame may conform tothe record of the case in the Patent Oflica.

Signed and sealed this 19th day of March, A. 1)., 1918,

swnj D u R. F. WHITEHEAD,

Acting Commissioner of Patients.

